The vacuum cleaner of the present invention is directed to a tank-type vacuum which is characterized by its use of cyclonic action to optimize its operation and performance. Examples of this type of vacuum cleaner are disclosed in U.S. Pat. Nos. 2,639,002 and 5,297,311. An explanatory description of the operation of these systems is provided below.
In general reference to FIG. 2, a tank-type vacuum cleaner has an inlet (for example, inlet 40) at a forward portion of the housing and which, whether directly or otherwise, enters a debris/dust collection receptacle (for example, bag 54) at an angle between approximately 10.degree. and approximately 85.degree.. This angle of entry requires inlet air to be forced against the wall of the receptacle (in reference to FIG. 2, see arrows). During operation, a continuous force is applied to the wall of the receptacle, thus preventing an accumulation of dust/debris at the wall adjacent to the vacuum motor assembly (for example, motor assembly M). Consequently, provided the collection receptacle maintains an appropriate level of dust/debris, a path between the air inlet and the motor assembly is largely uninterrupted or unobstructed. Other systems force air from an inlet through accumulated dust/debris. As more and more dust/debris accumulates, the vacuum cleaner motor must work harder to force an appropriate level of air through the system, thereby reducing efficiency and performance.
Conventional vacuum cleaner systems, whether tank-type or otherwise, consistently possess a number of shortcomings which inconvenience manufacturing, operation, use, or storage. An abbreviated description of at least a portion of such shortcomings is set forth below.
Conventional vacuum systems, whether tank-type or similarly constructed canister systems, typically have between 18 and 30 feet of power cord. When the vacuum cleaner is not in use, this length of cord can be quite burdensome to store. Common methods of storage include: wrapping the cord about the body of the vacuum, wrapping the cord about a cord wrap positioned on an upper surface of the vacuum, or using an automatic cord winder.
In regard to the first two alternatives, while also being aesthetically unappealing, these cord storage options may interfere with opening and closing compartments within and/or installing and removing components from the body of the vacuum. Automatic cord winders are relatively expensive and add considerable weight to a vacuum cleaner. Moreover, when an automatic cord winder is positioned on an underside of a vacuum cleaner, it typically increases the height of the canister/tank by several inches. The increased height of the canister/tank decreases the stability of conventional systems and increases the opportunity for such systems to tip over during use.
Conventional systems commonly do not include an adequate "downstream" air filtration system. Conventional vacuum systems instead rely upon a primary filter, for example, a disposable filter bag, and any downstream filter is limited to an open-cell foam or the like. While a filter bag may adequately remove particulates introduced into the vacuum, such filters do not address dust and the like added to air flowing through the vacuum, for example, by normal deterioration of a vacuum motor. The open-cell foams which are used are cosmetic in nature and offer no practical benefit in capturing fine particulates, controlling the exhaust, or muffling acoustic noise of the vacuum motor.
At least in the context of tank-type vacuums, these vacuums must typically be stored in a manner consistent with their use--resting on their wheels (or skids, as the case may be)--which limits different storage opportunities. Such limitation is due in part to the placement and orientation of the inlet relative to the device's collection receptacle. Specifically, conventional inlets allow inadvertent discharge of collected dust/debris when the system is stood on its forward end. As vacuums are typically stored more than they are used, a user evaluating different systems may place greater emphasis on their ability to easily store a vacuum cleaner as opposed to its quality or efficiency of operation.